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I appreciate the comments of Reeves and Ladner1 and Wiwanitkit.2 The use of electroencephalography (EEG) has been widely debated throughout the literature. In our investigation,3 which was limited to standard inpatient EEG, 96% of the EEGs performed did not change or contribute to clinical decision making. At this time, there are no national guidelines for EEG use, and EEGs are being employed for a wide spectrum of conditions, including altered mental status, epilepsy, seizure rule-out, syncope, cerebrovascular accident, and traumatic brain injury.

The shortfall of EEG is its low diagnostic sensitivity (25%-56%) and slightly higher specificity (78%-98%).4 Even in the presence of a normal EEG, patients can have a multitude of seizure disorders failing detection,4 while an abnormal EEG can correlate with specific underlying brain pathologies, such as Creutzfeldt-Jakob disease5 or burst suppression patterns.6 Although burst suppression patterns often correlate with poor prognoses, they do not point to any specific disease pathology and can be seen in traumatic brain injury and metabolic encephalopathy alike.6

The utility of EEG has, however, been demonstrated in intraoperative monitoring during carotid endarterectomy.7 Additionally, there have been evidence-based reviews published on its benefit in the evaluation of pediatric neurologic disorders8 and the management of newly diagnosed epilepsy.9

In the 2013 clinical practice guidelines for the management of pain, agitation, and delirium in adult patients in the intensive care unit (ICU), put forth by the American College of Critical Care Medicine, EEG was recommended (+1A; high quality, strong recommendation in favor of the intervention) to monitor nonconvulsive ICU patients with known or patients suspected of having seizure disorders or to titrate electrosuppresive medications in patients with elevated intracranial pressures.10 At our institution, in accordance with these guidelines, continuous EEG is used most commonly in patients with traumatic brain injuries, intracerebral hemorrhages, and cerebrovascular accidents to guide treatment.

Our study3 was limited to standard 23-channel, 30-minute recordings and cannot be extrapolated to include the utility of video EEG, 24-hour continuous EEG, or quantitative EEG. Regarding standard 23-channel, 30-minute EEG recordings, my coauthors and I believe that the level of utility is reflected in the appropriateness of ordering. In our study3 there were 8 cases (4%) in which EEG was performed that supported clinical decision making. In each of the EEGs with abnormal findings, indication for ordering EEG was consistent with the clinical practice guideline recommendations10 for use in ICU patients.

Unfortunately, 24% of our population had EEG performed for syncope, whereas previous studies11,12 have clearly shown that EEG was not valuable in treating patients with syncope. Smith et al13 examined appropriate use of EEG in comparison to the United Kingdom national guidelines for the use of EEG and found up to 40% of EEGs had been ordered inappropriately.

In the current political climate, I believe now more than ever, we as physicians are going to be asked to justify our health care expenditures. With a paucity of guidelines for EEG use, the responsibility falls to the physician to determine clinical utility. The goal of our study3 was to bring to light the common indications at our institution for ordering EEGs and the relatively small impact they had on clinical judgment in these cases.